While evolution is an accepted theory of how species evolve over time, and how new species spring from existing ones, the fundamental question of what actually started life on this planet is still the subject of a lot of conjecture.

ADVERTISEMENT

Some scientists postulate that rocks from space carrying life from other planets or perhaps asteroids landed on earth and found a favorable environment, and the evolutionary process was on!

New research indicates that microorganisms that crashed to Earth embedded in the fragments of distant planets might have been the sprouts of life on this one, according to research from Princeton University, the University of Arizona and the Centro de Astrobiología (CAB) in Spain.

The researchers report in the journal Astrobiology that under certain conditions there is a high probability that life came to Earth — or spread from Earth to other planets — during the solar system's infancy when Earth and its planetary neighbors orbiting other stars would have been close enough to each other to exchange lots of solid material. The work will be presented at the 2012 European Planetary Science Congress on Sept. 25.

The findings provide the strongest support yet for "lithopanspermia," the idea that basic life forms are distributed throughout the universe via meteorite-like planetary fragments cast forth by disruptions such as volcanic eruptions and collisions with other matter. Eventually, another planetary system's gravity traps these roaming rocks, which can result in a mingling that transfers any living cargo.

Previous research on this possible phenomenon suggests that the speed with which solid matter hurtles through the cosmos makes the chances of being snagged by another object highly unlikely. But the Princeton, Arizona and CAB researchers reconsidered lithopanspermia under a low-velocity process called weak transfer wherein solid materials meander out of the orbit of one large object and happen into the orbit of another. In this case, the researchers factored in velocities 50 times slower than previous estimates, or about 100 meters per second.